Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Insoluble trypsin has been shown to attack preferentially some peptide bonds of ovine prolactin, within the large disulfide loop. The peptide bond most susceptible to immobilized trypsin was identified as the Arg125-Leu126 of the ovine prolactin structure.
...
PMID:Studies on prolactin. 46. Preferential cleavage of the Arg125-Leu126 peptide bond of ovine hormone with immobilized trypsin. 711 95

A monoclonal antibody (mAb), designated PS-11.2, was generated by immunizing mice with recombinant porcine growth hormone (pGH). This antibody recognized GHs of porcine, bovine (bGH) and chicken (cGH) origins, but not human GH, ovine prolactin, somatostatin S-14, and GH-releasing factor (1-29)-NH2. Western analysis indicated that PS-11.2 predominantly identified not only the 22.5-kD protein but also its 45-kD dimer. It also recognized the 4.5- and 10-kD fragments of pGH resulting from trypsin digestion. The binding kinetics of PS-11.2 to pGH was determined by the biospecific interaction analysis in a real-time mode. The association and dissociation rate constants were estimated as 1.4 x 10(5) M-1 s-1 and 2.2 x 10(-4) s-1, respectively, thus producing an overall affinity of Kd = 1.6 x 10(-9) M. It partially inhibited the interaction of pGH and GH-binding protein in a competitive radioimmunoassay, suggesting that the pGH epitope recognized by PS-11.2 was closely related to the region responsible for engaging with GH receptors. Growth-deficient hypophysectomized rats were used for functional evaluation and shown to grow in response to the treatment of pGH. This effect was further augmented when pGH was administered together with PS-11.2, although antibody itself did not promote the growth of these animals. The antibody-mediated effect continued beyond the 5-day treatment period, indicating its long-lasting effect. Similar enhancement by PS-11.2 was also observed with bGH and cGH in this rat model.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Modulation of the effectiveness of growth hormone with a monoclonal antibody. 767 Nov 22

An effort was made to generate stable swine hybridomas capable of releasing monoclonal antibodies (MAb) with antigenic specificity. Crossbred pigs were immunized with recombinant porcine growth hormone (r-pGH) and the splenic cells were harvested from these animals. B lymphocytes enriched by gradient centrifugation and nylon wool adherence were briefly stimulated in vitro with r-pGH prior to hybridization with murine SP2/0 myeloma cells. The fused hybrids were screened for their ability to produce anti-pGH antibody and the positive ones were subcloned by a limiting dilution procedure. The stable cell lines were maintained by serial passages in cultures for further analysis. One such hybridoma, designated PM20/20, was found to secrete swine IgM. It recognized not only the immunizing r-pGH but also the native pGH extracted from the swine pituitary glands, as demonstrated by Western analysis. It also recognized two smaller fragments with m.w. of 10 kD and 5 kD of r-pGH following trypsin digestion. In addition to pGH, PM20/20 immunoreacted with several other GH species including bovine, chicken, and human origins, but not with ovine prolactin nor rat GH binding protein. The binding association rate constant and dissociation rate constant of PM20/20 to pGH were 5.3 x 10(4) M-1 s-1 and 1.0 x 10(-4) s-1, respectively, thus producing a dissociation constant of 1.9 x 10(-9) M. Therefore, stable swine-mouse heterohybridoma lines have been established and shown to continuously release swine mAb in cultures. These mAb may serve as useful alternatives to murine mAb in certain areas of research.
...
PMID:Generation of heterohybridomas capable of releasing swine monoclonal antibody specific to porcine growth hormone. 792 68

Photoaffinity labeling of ovine prolactin with the NAD+ photoaffinity analog [alpha-32P]nicotinamide-2-azidoadenine dinucleotide has been used to identify an NADH/NADPH binding site. Specificity of nucleotide interaction was demonstrated by saturation and protection of labeling at physiologically relevant concentrations. Saturation of photoinsertion was observed at approximately 100 microM probe with an apparent Kd of approximately 25 microM. Protection of photoinsertion was observed with NAD+ and NADH. The photoinsertion was decreased by 75% and greater than 95%, respectively, upon addition of 200 microM of the above-mentioned compounds. The protection obtained with NADP+ and NADPH was of the same order, respectively. The adenine ring binding domain of NADH/NADPH binding site was identified by trypsin and chymotrypsin digestion of the photolabeled prolactin and purification of the photolabeled peptide by boronate affinity chromatography and immobilized Fe3+ affinity chromatography. The peptide was identified to be Ala22-Tyr28. These studies demonstrate that prolactin contains an NADH/NADPH binding site which may be significant in the mechanism of action of this hormone.
...
PMID:Identification and characterization of a nucleotide binding site of ovine prolactin with 2-azido-NAD. 832 98

Ferret CL were collected on Days 5-11 of pregnancy or pseudopregnancy and incubated in McCoy's medium with radiolabeled amino acids to determine the ability of ferret CL to synthesize and secrete proteins during the preimplantation period. Products recovered from the medium were separated by one- and two-dimensional SDS-PAGE followed by fluorography and were quantified by densitometry. Selected secretory proteins were tentatively identified with specific antibodies on Western blots. Ferret CL synthesized and secreted a relatively large number of radiolabeled products. The predominant secretory proteins had molecular masses of 16, 22, 28, 32, 47, 68, and 185 kDa and were secreted at all stages of the preimplantation period. There were no qualitative changes in ferret luteal protein synthesis and secretion between Days 5-11 of pregnancy, and neither ovine prolactin (oPRL) nor dibutyryl cAMP (dcAMP) affected the pattern of protein secretion. However, oPRL (100 and 1000 ng/ml) increased incorporation of radiolabeled amino acids into luteal proteins during a 36-h incubation. The relative mobility of a 185-kDa radiolabeled product was identical to that of alpha 2-macroglobulin (alpha 2M) subunits. Antibody to human alpha 2M cross-reacted with a product (185 kDa) in ferret luteal extracts and culture medium, and the partially purified protein (185 kDa) inhibited trypsin activity. The major radiolabeled secretory protein (32 kDa) exhibited weak cross-reaction with antibody to a human tissue inhibitor of metalloproteinase (TIMP). This study demonstrates the wide range of proteinaceous secretory products of the ferret CL, two of which have been tentatively identified as protease inhibitors.
...
PMID:Luteal protein secretion during preimplantation in the ferret. 838 8

Environmental or nutritional estrogenic toxicants are thought to mediate developmental and carcinogenic pathologies. Estrogen receptor (ER) measurements are currently used to predict hormonal responsiveness; therefore all ER subpopulations should be considered. We have been involved in the immunoidentification and characterization of membrane steroid receptors in several systems and have recently shown that binding of estradiol (E2) to a subpopulation of ERs (mER) residing in the plasma membrane of GH3 pituitary tumor cells mediates the rapid release of prolactin (PRL). Here we review these findings and present other important characterizations of these receptors such as trypsin and serum susceptibility, movement in the membrane, confocal localization to the membrane, binding to and function of impeded ligands, and immunoseparation of cells bearing mER. We plan to use this system as a model for both the physiological and pathological nongenomic effects of estrogens and estrogenic xenobiotics. Specifically, it should be useful as an in vitro assay system for the ability of estrogenic xenobiotics to cause rapid PRL release as an example of nongenomic estrogen effects.
...
PMID:The other estrogen receptor in the plasma membrane: implications for the actions of environmental estrogens. 859 73

Incubation behavior in birds is characterized by elevated serum prolactin (PRL) levels. The objective of this study was to determine the cellular basis for increased PRL secretion. Incubation behavior of Bantam hens was induced by allowing the hens to accumulate their eggs. In experiment 1, hens were allowed to accumulate their eggs in floor pens for 0, 2, 12, or 24 days (Day 0, Day 2, Day 12, and Day 24 hens, respectively). Anterior pituitaries were dissociated into individual cells with trypsin, and the resulting cells were then subjected to reverse hemolytic plaque assays for PRL. The percentage of PRL-secreting cells and serum PRL levels were higher in Day 24 hens than in the other groups (p < 0.05; n = 3 separate trials). In experiment 2, hens were allowed to accumulate their eggs for 2, 14, 18, or 24 days (Day 2, Day 14, Day 18, and Day 24 hens, respectively). The percentage of PRL-secreting cells and levels of serum PRL were greater in Day 18 and Day 24 hens than in Day 2 hens (p < 0.05; n = 4). Results from Day 14 hens were intermediate and different (p < 0.05) from those from both Day 2 and Day 18 groups. Data indicate that an increase in the proportion of PRL secretors occurred between 14 and 18 days after hens began to accumulate their eggs. The area of plaques formed by lactotrophs from Day 14 and Day 18 hens was also increased (p < 0.05). In experiment 3, hens were allowed to accumulate their eggs for 0 and 24 days (Day 0 and Day 24 hens, respectively). Their anterior pituitaries were dissected into cephalic, middle, and caudal regions, and the percentage of PRL cells were analyzed in each region separately. The percentage of PRL secretors was increased (p < 0.05) in Day 24 compared to Day 0 hens in both the cephalic and middle regions of the anterior pituitary but not in the caudal portion. We conclude that increased PRL secretion during incubation behavior involves the recruitment of additional pituitary cells into the PRL-secreting population and an increase in the capacity of these cells to secrete hormone (p < 0.05). Furthermore, this increase in PRL-secreting cells is localized to the cephalic and middle regions of the anterior pituitary.
...
PMID:Cellular basis for elevated prolactin secretion during incubation behavior in Bantam chickens: analysis by reverse hemolytic plaque assay. 892 2

Proteases like trypsin, elastase, and many others play important regulatory functions by generating new biologically active molecules through limited proteolysis of larger proteins and peptides. The limited proteolysis of thyrotropin-releasing hormone (TRH) by Pyroglutamate aminopeptidase yields cyclo(His-Pro) or CHP, a new biopeptide associated with a variety of pharmacological activities, including regulation of body temperature, inhibition of prolactin secretion, and modulation of motor functions. Although the mechanism by which CHP elicits these biological activities is not well understood, it appears that the cyclic peptide may function at least in part by modulating central amine transport mechanisms.
...
PMID:Limited proteolysis and physiological regulation: an example from thyrotropin-releasing hormone metabolism. 982 68

In 14 volunteers, saliva from both parotid, submandibular and sublingual glands were collected by capsules under stimulation of sialosis with citric acid or alimentary trial breakfast. It was taken immediately and on the 1st and 3rd hours of postprandial response. In saliva and the blood serum, alpha-amylases, trypsin, common protein, thyrotropin, thyroxine, triiodthyronin, luteinizing hormone, follicle-stimulating hormone, prolactin, progesterone, oestradiol and hydrocortisone were assessed by means of immuno-assay technique. All but oestradiol hormones had a lower concentration in the saliva than in the blood serum. The concentration and deficits of hormones and trypsin in saliva of submandibular and sublingual glands is higher, than in saliva of parotid glands, the latter having a higher alpha-amylolytic activity. The share of p-amylase in comparison with s-amylase in saliva of parotid glands is lesser than in saliva of submandibular and sublingual glands. In alimentary stimulation of sialosis, the saliva with higher amylolytic and tryptic activity, higher concentration of thyrotropin and thyroxine was found than under a non-alimentary stimulation. After the 1st and the 3rd hours following a trial breakfast, in response to a non-alimentary stimulation of sialosis the saliva was found to preserve properties of a postprandial saliva.
...
PMID:[Postprandial transformations of enzymatic and hormonal properties of saliva and blood]. 1201 35

RT-PCR followed by 5'- and 3'- rapid amplification of cDNA ends was used to clone and sequence ovine prolactin-releasing peptide (PrRP). The cDNA was characterised by short 5'- and 3'-untranslated regions and a GC-rich (71%) coding region. The nucleotide and deduced amino acid sequences for the coding region showed 95.6 and 94.9% identity with bovine PrRP but the amino acid sequence of PrRP31 was conserved between these species. Northern blot analysis and RT-PCR showed that, as in the rat, the peptide was more abundantly expressed in the brainstem than the hypothalamus. However, in the ovine hypothalamus, PrRP mRNA expression was more widespread than in the rat, with expression detected in both rostral and caudal parts of the mediobasal hypothalamus. The effects of synthetic ovine PrRP on prolactin secretion both in vitro and in vivo were also examined. In primary cultures of sheep pituitary cells, PrRP significantly (P<0.01) increased prolactin concentrations in the culture medium but the response was not observed in every experiment and was only seen when pituitary glands were dispersed with collagenase rather than trypsin. PrRP was much less potent than TRH which caused a significant (P<0.01) two- to threefold increase in prolactin concentrations in every experiment. Intravenous (10 and 50 nmol) or intracerebroventricular (10 and 50 nmol) injection of PrRP had no significant effect on either plasma prolactin concentration or pulsatile LH secretion whereas intravenous injection of TRH (10 nmol) produced a highly significant (P<0.01) and more than sevenfold stimulation of plasma prolactin concentrations. In conclusion, these results suggest that PrRP is unlikely to be an important prolactin-releasing factor in this species.
...
PMID:Prolactin-releasing peptide in the ewe: cDNA cloning, mRNA distribution and effects on prolactin secretion in vitro and in vivo. 1209 62


<< Previous 1 2 3 4 5 6 7 8 Next >>

---